EP0510488B1

EP0510488B1 - Lid for wide-mouthed container and method for making the same

Info

Publication number: EP0510488B1
Application number: EP92106413A
Authority: EP
Inventors: Yoshiaki C/O Tenryu Chemical Ind. Co.Ltd Yoshida
Original assignee: Tenryu Chemical Industry Co Ltd
Current assignee: Tenryu Chemical Industry Co Ltd
Priority date: 1991-04-22
Filing date: 1992-04-14
Publication date: 1995-10-04
Anticipated expiration: 2012-04-14
Also published as: EP0510488A1; CN1066037A; DE69205200D1; US5328045A; KR920019636A; US5395005A; DE69205200T2

Description

This invention relates to a lid device according to the preamble of claim 1. The invention also relates to a method of making such a lid device according to the preamble of claim 11.
In general, a lid device of the above-described type is made by forming a metallic plate of e.g. aluminum or tin into a predetermined shape to provide a lid body with an opening, and directly attaching a closure film (e.g. aluminum foil or resin film) to the lid body for closing the opening. In use, the closure film is peeled off the closure film to provide access into the container.
Typically, the closure film is attached to the lid body by utilizing the heat sealing method, as disclosed in U.S. Patent to Bloeck et al or Japanese Utility Model Application Laid-open No. 62-108229 (Inventors: Susumu TAKADA et al.). Specifically, according to the known heat sealing method, a bonding layer of thermally meltable adhesive or thermoplastic resin is preliminarily formed on the lid body and/or the closure film, and a hot plate is pressed against the closure film overlapped on the lid body to cause thermal fusion of the bonding layer.
The heat sealing method provides uniform attachment of the film over the entire circumference thereof as long as the lid body has a strictly flat attachment surface. In reality, however, it is difficult to make the attachment surface of the lid body strictly flat because the lid body is subjected to various forces at the time of forming from a metallic plate. Thus, the hot plate for heat sealing may pressed unevenly circumferentially of the film, which results in uneven attachment of the film. In an extreme case, the film may be left non-attached at one or more circumferential positions, which causes unexpected gas entry and/or leakage at the non-attached positions.
A lid device for wide-mouthed container according to the preamble of claim 1 is known from EP-A-392 078. The lid device for this document comprises a resinous closure member which includes a central portion integrally connected to an enlarged outer margin for fixation of the closure member to a lid body. The central portion of the closure member is integrally connected to a pull tab which is used to tear-open the closure member along a weakening line. The lid device further comprises as an auxillary element, which may be dispensed within an application requiring no strict gas tightness, an aluminium foil attached to the closure member for improving the gas tightness of the closure member. However, the use of the enlarged outer margin as an independent element is improper because it forms an essential part of the tear-open type closure member. Further, since the aluminium foil is perforated by the pull tab, it is impossible for the aluminium foil alone to completely close the opening of the lid body.
EP-A-59635 discloses a lid device which includes as a rim member a covering layer made of a thermoplastic resin having a heat-bondability for heatbonding to a cut edge of a can end member. The covering layer is formed by heat sealing two film layers which are extremely thin, and the structure of the covering layer requires that the can end member has a flat inner edge. Advantageously, this flat structure of the inner edge may allow the covering layer to slip off easily when the closure film is peeled off, thereby exposing the sharp edge of the can end member. Further, due to the extremely small thickness of the film layers the rim member is likely to have sharp edges even after heat sealing.
It is an object of the present invention to provide a lid device for a wide-mouthed container according to the preamble of claim 1 and a method of making such a lid device according to the preamble of claim 11 wherein a closure film can be uniformly attached to hermetically closing the opening of said metallic lid body.
According to the present invention this object is obtained for a lid device by the characterizing portion of claim 1 and for a method of making such a lid device according to the characterizing features of claim 11.
Further advantageous embodiments of the lid device are characterized in dependent claims 2 - 10, whereas further advantageous embodiments of the method are characterized in dependent claims 12 - 17.
Advantageously, according to the invention, the closure film can be uniformly attached to the flat surface of the rim member by various known methods for reliably closing the opening of the lid body and the closure film means may have a tap portion extending beyond the rim member or alternatively an own peripheral portion extending beyond the rim member for facilitating manual peeling of the film means.
Further, unexpected tearing of the closure film means can be prevented by provision of a reinforcing member according to dependent claim 4 and alternative embodiments as claimed in dependent claim 5 - 7, respectively.
According to the method of the invention, the inherent stickiness and injection pressure of the fluid resin can be effectively utilized for uniformly attaching the closure film to the rim member without the necessity of subsequently performing a separate attaching step. Thus, the quality of the lid device is enhanced at lower cost.
In case the lid device is made to further incorporate a resinous reinforcing member and a pull tab integral with the reinforcing member, these components may be preferably molded together with the rim member. In this case, the overall manufacturing process can be greatly simplified to reduce the production cost.
When the inner margin of the lid body is bent to have an anchoring recess, the method may further comprises the step of compressing the rim member to reduce the width of the anchoring recess after the fluid resin hardens. This additional process step improves hermetical ability at the connection between the lid body and the rim member.
Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments given with reference to the accompanying drawings; in which:

Fig. 1 is perspective view showing a wide-mouthed container which is closed by a lid device according to a first embodiment of the present invention;
Fig. 2 is a perspective view similar to Fig. 1 but showing the container which has been opened;
Fig. 3 is a sectional view taken along lines III-III in Fig. 1;
Fig. 4 is an enlarged fragmentary sectional view showing an example of closure film to be incorporated into the lid device of Fig. 1;
Fig. 5 is a perspective view showing a lid device, in an inverted state, according to a second embodiment of the present invention;
Fig. 6 is a fragmentary sectional view taken along lines VI-VI in Fig. 5;
Fig. 7 is a sectional view showing the lid device of Fig. 5 in its partially opened state;
Fig. 8 is a perspective view showing a principal portion of the lid device of Fig. 5 in its partially opened state;
Fig. 9 is a perspective view which is illustrative of the problem to be solved by the second embodiment;
Fig. 10 is a plan view showing a lid device according to a third embodiment of the present invention;
Fig. 11 is a fragmentary sectional view taken along lines XI-XI in Fig. 10;
Fig. 12 is a plan view showing a lid device according to a fourth embodiment of the present invention;
Fig. 13 is a plan view showing a lid device according to a fifth embodiment of the present invention;
Fig. 14 is a fragmentary sectional view taken along lines XV-XV in Fig. 13;
Fig. 15 is a plan view showing a lid device according to a sixth embodiment of the present invention;
Fig. 16 is a plan view showing a lid device according to an seventh embodiment of the present invention;
Fig. 17 is a fragmentary sectional view taken along lines XVIII-XVIII in Fig. 16;
Fig. 18 is a plan view showing a lid device according to a eighth embodiment of the present invention;
Fig. 19 is a fragmentary sectional view taken along lines XX-XX in Fig. 18;
Fig. 20 is a fragmentary sectional view showing a lid device according to a ninth embodiment of the present invention;
Fig. 21 is a fragmentary sectional view showing a lid device according to an tenth embodiment of the present invention;
Fig. 22 is a sectional view showing a mold used in a method for making the lid device according to the first embodiment illustrated in Figs. 1 to 4;
Fig. 23 is a view showing the same mold as seen in the direction of arrows XXX-XXX in Fig. 22;
Fig. 24 is a sectional view showing the same mold in its closed condition;
Figs. 25 and 26 are views showing a method for making the lid device according to the second embodiment illustrated in Figs. 5 to 8;
Fig. 27 is a sectional view showing a method for improving hermetical ability for the lid device according to each foregoing embodiment;
Figs. 28 and 29 are fragmentary sectional views illustrating how and why the hermetical ability is improved by the method shown in Fig. 27;
Fig. 30 is a fragmentary plan view showing another method for improving hermetical ability; and
Fig. 31 is a fragmentary sectional view taken along lines XXXXI-XXXXI in Fig. 30;

mouthed container

open mouth

lid device

The lid device 2 includes a lid body 3 formed to have a concentric opening 4 which is normally closed by a closure film 5. The lid body 3, which may be made of a thin metal plate, has an outer mounting margin 3a which is shaped in an inverted U for fitting to the top open mouth 1a of the container 1 by a known method such as hemming or caulking. A packing 7 made of rubber or other soft material is interposed between the lid mounting margin 3a and the container mouth 1a to hermetically seal the interior of the container.
The lid body 3 further has a flat portion 3b formed with an inner anchoring margin 3c. The anchoring margin 3c is bent radially outward into a hook shape and entirely enclosed in an annular rim member 6 which is made of relatively soft synthetic resin. Since the rim member 6 is located radially inwardly from the outer mounting margin 3a of the lid body 3, the flat portion 3b of the lid body is partially exposed.
The closure film 5 has an annular peripheral portion 5e peelably attached to the upper surface (outer surface) of the rim member 6, and a tab portion 5a projecting beyond the rim member 6. The film 5 may comprise a single layer which is made of metallic foil (e.g. aluminum foil), resin, paper and so on. Alternatively, the film 5 may comprise multiple layers which typically include a core layer 5b and two surface layers 5c, 5d attached to both surfaces of the core layer 5b by coating or bonding, as shown in Fig. 4.
When the laminate structure shown in Fig. 4 is adopted for the closure film 5, the respective layers 5b-5d may be made of various materials. For instance, the core layer 5b may be made of tough paper (e.g. milk carton paper), whereas the surface layers 5c, 5d may be made of metallic foil (e.g. aluminum foil) or synthetic resin (e.g. polyethylene terephthalate). Alternatively, the core layer 5b may be made of aluminum foil, whereas the surface layers 5c, 5d may be made of synthetic resin. Indeed, the materials for the respective layers 5b-5d may be optionally selected depending on various requirements which include gas-imperviousness, printing capability, disposability after use, and so on.
The closure film 5 may be attached to the rim member 6 by various methods. For example, the film 5 is made to have a peripheral portion provided with hot-melt resin or adhesive which is thermally fused for attachment to the rim member 6. Thermal fusing of the hot-melt resin may be performed by utilizing a heating plate (as in the heat sealing method), a microwave generator (as in the high-frequency sealing method), or a supersonic generator (as in the supersonic sealing method). Obviously, in such thermal fusing, the rim member 6 itself can be partially fused for uniform attachment to the film 5 even if the flat portion 3b of the lid body 3 does not have strict flatness.
Alternatively, the inherent stickiness of the rim member 6 itself may be utilized for attachment to the closure film 5. Specifically, the rim member 6 has a certain degree of stickiness at the time of molding from fluid resin, so that the film 5 can be attached to the rim member 6 by introducing the film into a mold at the time of forming the rim member, as more concretely described later with reference to Figs. 29-31. In this case, the pressure of the fluid resin upon injection acts uniformly to realize uniform attachment of the film 5 relative to the rim member 6.
To strengthen the attachment of the film 5 relative to the rim member 6, the film 5 as a whole (in the case of having a single layer structure) or the bottom surface layer 5d of the film 5 (in the case of having the laminate structure of Fig. 4) may be made of the same resinous material as the rim member 6. Further, the surfaces of the lid body 3 may be coated with a resinous material (preferably identical to that for the rim member 6), thereby strengthening fixation of the rim member 6 relative to the lid body 3.
Obviously, the lid device 2 can be easily opened by manually pulling up the tab portion 5a of the closure film 5. As a result, the film is peeled off the rim member 6 which itself is firmly fixed to the bent inner anchoring margin 3c of the lid body 3. The remaining rim member 6 serves as a safe guide at the time of manually taking out the content of the opened container 1.
Figs. 5-8 shows a lid device 2 according to the second embodiment of the present invention. Similarly to the first embodiment, the lid device of the second embodiment includes a lid body 3, a closure film 5, and a rim member 6. However, the lid device of the second embodiment additionally includes a peripheral reinforcing member 8 which is in the form of a ring attached to the inner surface of the film 5 and slightly spaced from the rim member 6 by a small amount e (see Fig. 6).
At the time of peeling the film 5 off the rim member 6, a pulling force F (see Fig. 8) acts concentratively at the tab portion 5a and is directed radially of the film, whereas peeling of the film occurs circumferentially. Therefore, the tensile direction and the peeling direction do not coincide to result in generation of a tearing force. Thus, if the film has no peripheral reinforcement, the film may be torn in the tensile direction to result in incomplete opening of the lid device, as shown in Fig. 9. This problem is particularly remarkable if the film is made entirely or mainly of a weak material such as paper or if the film is extremely thin.
The reinforcing member or ring 8 reinforces the peripheral portion 5e of the film 5 to effectively prevent unexpected tearing of the film at the time of peeling. As a result, the lid device can be opened completely at all times. Preferably, the annular gap e (Fig. 6) should be as small as possible.
Figs. 10 and 11 show a lid device 2 according to the third embodiment of the present invention. The lid device of the third embodiment includes a reinforcing member 8 which is discal instead of annular.
Obviously, the discal reinforcing member 8 provides an increased area for attachment to the film 5. Thus, the film is prevented not only from tearing but also from sagging in its central portion even if the film is thin.
Fig. 12 shows a lid device 2 according to the fourth embodiment of the present invention. The lid device of the fourth embodiment differs from that of the second embodiment (Figs. 5-8) only in that the reinforcing member 8 is arcuate. Alternatively, the reinforcing member may be generally semicircular, as indicated by a chain line in Fig. 12.
The problem of tearing is most likely to occur at the time of starting peeling the film 5 because the tensile force is applied locally at the tab portion 5a. No such tearing occurs when the peeling operation proceeds beyond the half way. Thus, the reinforcing member 8 need not be completely annular or discal.
Figs. 13 and 14 represent a lid device 2 according to the fifth embodiment of the present invention. The lid device of this embodiment is similar to that of the second embodiment (Figs. 5-8) except that the reinforcing member or ring 8 is attached to the closure film 5 outside the container 1 and located to substantially overlap the rim member 6.
Obviously, the tearing preventing function of the reinforcing member 8 is improved when it is attached to the outer surface of the closure film 5, because the film tap portion 5a upon pulling up for peeling comes into stopping engagement with the reinforcing member 8. Further, the tearing preventing function of the reinforcing member 8 is additionally improved by the fact that it substantially overlaps the rim member 6 because the diameter of the rim member 6 (i.e., the reinforcing member 8) corresponds substantially to that of the closure film 5.
Of course, the externally arranged reinforcing member 8 shown in Figs. 13 and 14 may be positioned radially inwardly from the rim member 6. Further, the reinforcing member 8 may be discal, arcuate or semicircular. In case the closure film 5 carries printed information, the reinforcing member 8 may be made of transparent resin to enable visual recognition of the printed information under the reinforcing member.
Fig. 15 illustrates a lid device 2 according to the sixth embodiment of the present invention. The lid device of this embodiment comprises a closure film 5 which is made to have an entire peripheral portion 5e extending beyond the rim member 6. The lid device further includes a discal reinforcing member 8 attached to the inner surface of the closure film 5.
According to the sixth embodiment of Fig. 15, the closure film 5 has no tab portion. Instead, peeling of the film 5 may be started at any circumferential position by utilizing the excess peripheral portion 5e of the film. Of course, the discal reinforcing member 8 may be replaced by a reinforcing ring attached to the outer surface of the film 5 near the excess peripheral portion 5e thereof.
Figs. 16 and 17 show a lid device 2 according to the seventh embodiment of the present invention. In this embodiment, the rim member 6 has an integral scraping strip 6b extending transversely of the rim member. As a result, the opening 4 of the lid body 3 is divided into two sections which are equally closed by a single closure film 5 attached to the rim member 6 including the scraping strip 6b. A pair of generally semicircular reinforcing members 8 are attached to the inner surface of the closure film 5 at the respective divided sections of the lid body opening 4.
It is now assumed that the container 1 contains powder or granular material 11 (see Fig. 17) such as milk powder which is scooped by a spoon 10 after peeling off the closure film 5. The scraping strip 6b may be utilized to scrape off an excess portion of the thus scooped powder, thereby enabling to take out a predetermined amount of powder upon every scooping.
The scraping strip 6b shown in Figs. 16 and 17 may be replaced by a scraping rod 6b' (indicated by chain lines in Figs. 16 and 17) which is spaced from the film 5 without direct attachment thereto. Further, the single film 5 may be replaced by a pair of separate films corresponding to the respective divided sections of the lid body opening 4.
Figs. 18 and 19 represent a lid device 2 according to the eigth embodiment of the present invention. In this embodiment, the lid body 3 is shaped to have an opening 4 which includes a straight portion 4a, and the rim member 6 is similarly made to have a straight portion 6d. Apparently, the straight portion 6d of the rim member may be utilized for scraping powder material 11 scooped by a spoon 10 after peeling off the closure film.
In the eigth embodiment of Figs. 18 and 19, the closure film 5 is entirely circular, so that it has a peripheral portion 5e located beyond the straight portion 6d of the rim member 6 to serve as a tab for peeling off the film. Preferably, the rim member 6 may be made to have an integral outward extension 6c for reliable sealing without using a separate packing.
Fig. 20 shows a lid device 2 according to the ninth embodiment of the present invention. In this embodiment, the rim member 6 is made to have an integral extension 6c which is also formed integrally with a packing 7'.
In the ninth embodiment of Fig. 20, the rim member 6 (with the integral extension 6c) and the packing 7' may be simultaneously formed in a single molding step. During the molding step, fluid resin (e.g. polyethylene) for the rim member 6 is fused to different fluid material (e.g. rubber) for the packing 7'.
Obviously, the rim member 6 alone can provide reliable sealing between the lid body 3 and the rim member 6 as well as between the lid body 3 and the container (not shown in Fig. 20). The packing 7' additionally improves sealing between the lid body 3 and the container.
Fig. 21 illustrates a lid device 2 according to the tenth embodiment of the present invention. In this embodiment, the bent inner anchoring margin 3c is covered, on both surfaces, with adhesive layers 3d prior to forming the rim member 6. The material for the adhesive layers 3d is selected so that it provides excellent adhesion both to the metallic lid body 3 and the resinous rim member 6. Obviously, the additional provision of the adhesive layers 3d improves sealing between the lid body 3 and the rim member 6 in addition to enhancing fixation of the rim member.
Figs. 22-24 illustrate a method for making the lid device shown in Figs. 1-4 (first embodiment). The illustrated method utilizes a first mold member 17 and a second mold members 18.
The first mold member 17 has an annular rim forming cavity 19 and an annular support face 17a arranged immediately around the rim forming cavity 19. The first mold member further has a runner or sprue 20 communicating with the rim forming cavity 19.
The second mold member 18 has a central film receiving cavity 21 and an annular shoulder 18a located immediately around the film receiving cavity 21. The annular shoulder 18a of the second mold member 18 corresponds in position to the annular support face 17a of the first mold member 17.
In manufacture, the closure film 5 is directly held in the film receiving cavity 21 of the second mold member 18 by applying vacuum for example, as shown in Fig. 29. In this condition, the tab portion 5a of the film 5 rests on the annular shoulder 18a. Instead, the tab portion 5a may be folded behind the film within the film receiving cavity 21, so that the tab portion 5a is completely concealed by the film. The application of vacuum may be performed through holes (not shown) formed in the second mold member. Alternatively, the film may be held in the film receiving cavity 21 by utilizing electrostatic attraction between the film (negatively charged for example) and the second mold member 18 (positively charged for example).
Then, the flat portion 3b of the lid body 3 is interposed between the support face 17a of the first mold member 17 and the annular shoulder 18a of the second mold member 18. In this condition, fluid resin 22 is injected under pressure into the rim forming cavity 19 of the first mold member 17 through the runner 20.
Upon hardening, the injected resin 22 provides the rim member 6 which encloses the bent inner anchoring margin 3c and is attached to the film 5 by utilizing the inherent stickiness of the fluid resin. On the other hand, since the tab portion 5a of the film 5 is interposed between the lid body 3 and the annular shoulder 18a of the second mold member 18 (or concealed behind the film), the film tab portion 5a remains non-attached for enabling subsequent peeling of the film. Further, the forceful interposition of the flat portion 3b of the lid body between the annular support face 17a of the first mold member 17 and the annular shoulder 18a of the second mold member 18 makes it possible to prevent flash formation at the time of molding the rim member.
According to the method described above, the injection pressure of the fluid resin 22 acts uniformly on the film 5 at the rim forming cavity 19. Thus, the inherent stickiness of the fluid resin can be effectively utilized for uniformly attaching the film 5 to the rim member 6 (see Figs. 1-4) without the necessity of performing a separate film attaching step. Further, such uniform attachment of the film is realizable even if the thickness of the film is relatively large and uneven. On the other hand, the use of thermal fusing may result in uneven and/or slow attachment when the film is excessively thick.
The film 5 may be supplied to the film receiving cavity 21 of the second mold member 18 by a vacuum suction collet (not shown) which picks it up from a stack of such films and transfers it to the location of the second mold member. Indeed, the use of the suction collet is enabled because the film, which is subsequently attached to the rim member 6 by utilizing the inherent stickiness of the fluid resin 22, may be thick enough to enable proper suction pick-up.
Instead of directly placing the closure film 5 in the film receiving cavity 21 of the second mold member 18, the film 5 may be provisionally attached to the lid body 3 by relatively weak adhesive applied to the annular peripheral portion 5e of the film, as indicated by phantom lines in Fig. 29. In this case, the film may be kept taut even if it is relatively thin, so that the film together with the lid body 3 may be transported to the location of molding by using a vacuum suction collet. Obviously, the film comes off the lid body under the pressure of the injected fluid resin 22 at the time of molding the rim member 6.
Figs. 25 and 26 illustrate a method which is suitable for making the lid device shown in Figs. 5-8 (second embodiment). The method of this embodiment is similar to that of Figs. 22-24 but differs therefrom only in that the first mold member 17 additionally has an annular reinforcement forming cavity 23 and a runner 24 communicating with the cavity 22.
In manufacture, fluid resin 22 is injected under pressure through the respective runners 20, 23. As a result, the ring-form reinforcing member 8 and the annular rim member 6 (see Figs. 5-8) are simultaneously formed and attached to the film 5 in a single molding step, so that the manufacturing process is greatly simplified to reduce the production cost.
Obviously, the configuration of the reinforcement forming cavity 23 may be modified so that the molded reinforcing member 8 becomes discal (third embodiment of Figs. 10 and 11), arcuate or semicircular (fourth embodiment of Fig. 12).
Instead of the first mold member 17, the second mold member 18 may be modified to have a reinforcement forming cavity 23 in communication with a runner 24, as indicated by chain lines in Fig. 25. In this case, the lid device shown in Figs. 13 and 14 (fifth embodiment) will result.
The lid device shown in Fig. 15 (sixth embodiment) may be obtained simply by interposing the entire peripheral portion 5e of the film 5 between the flat portion 3b of the lid body 3 and the annular shoulder 18a of the second mold member 18. Further, the lid device shown in Figs. 16-17 (seventh embodiment) or 18-19 (eigth embodiment) may be obtained simply by modifying the configuration of the rim forming cavity 19 and the reinforcement forming cavity 23.
Of course, the reinforcing member 8 may be separately prepared and later attached to the film 5 by adhesive which is curable by drying, heating or ultraviolet radiation. Alternatively, the separately prepared reinforcing member 8 may be attached to the film 5 by the heat sealing method or any other method.
Fig. 27 shows a method of improving hermetical ability at the connection between the lid body 3 and the rim member 6 with respect to the lid device according to the second embodiment (Figs. 5-8). Of course, the same method is applicable to the lid devices of other embodiments. Before describing the method per se, reference is made to Fig. 29 to explain why it is necessary to improve hermetical ability.
As shown in Fig. 29, the rim member 6 encloses the bent inner anchoring margin 3c of the lid body 3 and has an interior anchoring portion 6e received in the recess 3e of the anchoring margin 3c. The rim member 6 is made by molding from fluid synthetic resin which generally has tendency of volumetrically contracting upon hardening, as indicated by single-headed arrows in Fig. 29. Thus, there is a possibility that minute clearances are formed between the anchoring margin 3c and the rim member 6 along the surfaces of the anchoring margin. As a result, gases and/or moisture content may pass through the minute clearances into or out of the container, as indicated by double-headed arrows C in Fig. 29.
According to the method of Fig. 27, the rim member 6 together with the inner anchoring margin 3c of the lid body 3 is compressed by a pair of presser members 29, 30 after hardening of the rim member. As a result, the inner anchoring margin 3c of the lid body is collapsively deformed to reduce the width of the recess 3e, as shown in Fig. 28. In this way, the interior anchoring portion 6e of the rim member is brought into intimate contact with the inner anchoring margin 3c, and the minute clearances are interrupted to improve hermetical ability.
In Fig. 27, compression of the rim member 6 is performed by utilizing the pair of presser members 29, 30 after taking out the lid device 2 from the respective mold members 17, 18 (see Figs. 25 and 26). However, the mold members 17, 18 may be modified to have an additional function of compressing the rim member 6, thereby enabling to perform molding and compressing in immediate succession.
Compression of the rim member 6 may be performed by utilizing a presser roller 29', as shown in Figs. 30 and 31. In this case, the lid device 2 is supported on a presser base 30' preferably in an inverted state, and the presser roller 29' is made to roll on the rim member 6 along the annulus thereof. Obviously, the use of the presser roller 29' is advantageous in that it is capable of uniformly pressing the rim member even if the thickness thereof is uneven.

Claims

A lid device for a wide-mouthed container (1), comprising:
a metallic lid body (3) fittable to an open mouth (1a) of the container (1);
said lid body (3) having an inner margin (3c) bent so as to form an anchoring means for a moulded resinous portion;
said resinous portion extending along the inner margin of the lid body (3) for defining an opening (4) of a predetermined shape; and
a film means (5) peelably attached to an outer surface of said resinous portion;
characterised in that
said resinous portion is a rim member (6), and
said film means (5) is formed continously without perforation thereby closing the entire opening (4) formed by said rim member (6).
The lid device according to claim 1, wherein the closure film means (5) has a tab portion (5a) extending beyond the rim member (6).
The lid device according to claim 1, wherein the closure film means (5) has at least a part of its peripheral portion (5e) extending beyond the rim member (6).
The lid device according to a preceding claim, further comprising a resinous reinforcing member (8) attached to the closure film means (5), the reinforcing member (8) being separate from the rim member (6) but having periphery located adjacent to the rim member (6), the closure film means (5) extending beyond the periphery of the reinforcing member (8).
The lid device according to claim 4, wherein the reinforcing member (8) is smaller than the opening (4) of the lid body (3).
The lid device according to claim 4, wherein the reinforcing member (8) is attached to an axially inner face of the closure film means (5).
The lid device according to claim 4, wherein the reinforcing member (8) is attached to an axially outer face of the closure film means (5).
The lid device according to a preceding claim, wherein the rim member (6) has a substantially straight scraping portion (6b, 6b', 6d).
The lid device according to claim 8, wherein the scraping portion (6b, 6b') traverses the opening (4) of the lid body (3) to divide the opening (4) into two sections.
The lid device according to a preceding claim, wherein the rim member (6) has an integral outward extension (6c) which seals between the lid body (3) and the open mouth (1a) of the container (1).
A method of making the lid device defined in claim 1 by using a first mold member (17) and a second mold member (18), the first mold member (17) having a rim forming cavity (19) and a support face (17a) around the rim forming cavity, the second mold member (18) having a film receiving cavity (21) and a shoulder (18a) around the film receiving cavity, the method comprising the steps of:
arranging the lid body (3) and the closure film means (5) between the first and second mold members (17, 18) with the closure film (5) means located between the lid body (3) and the second mold member (18);
bringing the first and second mold members (17, 18) toward each other so that the lid body (3) is sandwiched between the support face (17a) of the first mold member (17) and the shoulder (18a) of the second mold member (18); and
injecting fluid resin (22) into the rim forming cavity (19) under pressure.
The method according to claim 11, wherein the closure film means (5) is arranged between the first and second mold members (17, 18) separately from the lid body (3), the closure film means (5) being preliminarily received intimately in the film receiving cavity (21) before the first and second mold members (17, 18) are brought toward each other.
The method according to claim 11, wherein the closure film means (5) is provisionally attached to the lid body (3) and arranged between the first and second mold members (17, 18) together with the lid body (3) before the first and second mold members (17, 18) are brought toward each other.
The method according to claim 11, wherein a portion (5a, 5e) of the closure film means (5) is made to rest on the shoulder (18a) of the second mold member.
The method according to claim 11, wherein the method further comprises the step of compressing the rim member (6) to reduce the width of the anchoring recess after the fluid resin (22) hardens.
The method according to claim 11, wherein the first mold member (17) further has a reinforcement forming cavity (23), and fluid resin (22) is also injected to fill the reinforcement forming cavity (23).
The method according to claim 11, wherein the second mold member (18) further has a reinforcement forming cavity (23), and fluid resin (22) is also injected to fill the reinforcement forming cavity (23).